Lawyering Compilation from I.W.F.

Well, since there is no official ruling we decided with my friends that yes, you have to make the breakaway roll for the carried monster, since Giants have to do a breakaway roll too to move.
But! to keep all parties happy we also decided that if the Giant has zero action tokens the breakaway roll for the carried monster would be from 3-6; instead of 4-6 as normal. To give the idea of being taken and carried away by a Giant more sense.

And that is the great issue with Horrorclix, I sometimes feel that the developers didn't played enough to make the rulebook, and left with the players a lot of holes on the rules that they have to fill someway or another in order to carry on with the game in an organized matter.

Of course this is a hoserule you can fill the holes in the rules as you want, I recommend newcomers to play strictly by the rules to squeeze the most fun out of Horrorclix